Back to results
US 6,681,583 B2Granted
Control unit for clutchless, variable displacement compressor
AssigneeSanden Corporation
InventorYukihiko Taguchi
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeSanden Corporation
InventorYukihiko Taguchi
Estimating the term…
A control unit for a clutchless variable displacement compressor with a solenoid is used in an air conditioning system for vehicles. The control unit includes a solenoid drive for adjusting a current flowing in the solenoid, a voltmeter for detecting a voltage applied to the solenoid, an ammeter for detecting the current of the solenoid, and a control for supplying current to the solenoid drive during a first predetermined time period when the air conditioning system is not in operation, and current has been prevented from flowing to the solenoid during a second predetermined time period. A resistance of a coil of the solenoid is calculated from the detected voltage and the detected current. A temperature of the compressor is determined from the calculated resistance based on a predetermined relationship between the resistance and the temperature of the coil of the solenoid when the air conditioning system is not in operation; the compressor is operated by supplying current to the solenoid when the calculated temperature exceeds a set value. Thus, the temperature of the compressor may be detected by a control mechanism, and the compressor may be protected against an excessive increase of temperature.
A control unit for a clutchless, variable displacement compressor used in air conditioning systems for vehicles, said compressor having a solenoid, such that discharge displacement of said compressor is controlled by adjusting a pressure in said compressor by a control valve operated by controlling a current flowing in said solenoid, said control unit comprising:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
By varying the relative positions of a swash plate and a cylinder block: controlled by crankcase pressure
Using compression: characterised by safety arrangements, e.g. compressor anti-seizure means or by signalling devices
Control using electricity: and making use of computers
For compression type machines, plants or systems: compressor control arrangements
Term ended 21 Nov 2022 (estimated)
1. Field of the Invention
The present invention relates to a control unit for a clutchless, variable displacement compressor used in air conditioning systems for vehicles and operated in response to an external signal.
2. Description of Related Art
Further objects, features, and advantages of the present invention will be understood from the following detailed description of preferred embodiments of the present invention with reference to the accompanying figures.
Embodiments of the invention are now described with reference to the accompanying figures, which are given by way of example only, and are not intended to limit the disclosure of the present invention.
FIG. 1 is a block diagram of a control unit for a variable displacement compressor according to an embodiment of the present invention.
FIG. 1 shows a constitution of a control unit for a variable displacement compressor, according to an embodiment of the present invention. Referring to FIG. 1, a control unit 1 is depicted for a variable displacement compressor 2, and variable displacement compressor 2 is driven without use of a clutch by a rotational force transmitted from a prime mover, such as an engine for a vehicle. Control unit 1 comprises a control circuit 3 and a power source line 4.
Variable displacement compressor 2 has a control valve solenoid 10. One of the terminals of control valve solenoid 10 is connected to power source line 4 of the vehicle through solenoid drive means 11 for adjusting a current flowing in solenoid 10 and current detection means 12 for detecting a current flowing solenoid 10, and the other terminal is connected to a grounded line 5. Current detection means 12 comprises a resistor the resistance value of which is known. A diode 13 is coupled in parallel to control valve solenoid 10 to form a free wheel circuit. Solenoid drive means 11 comprises switching elements, each of which operates ON/OFF at a predetermined frequency. Solenoid drive means 11 adjusts a current flowing in control valve solenoid 10 by changing the ON/OFF ratio (duty ratio). For example, at a duty ratio of zero, the switches of solenoid drive means 11 are opened, the flow of current to control valve solenoid 10 is interrupted, and the displacement of variable displacement compressor 2 approaches a minimum. At a duty ratio of 100%, however, the switches of solenoid drive means 11 are closed, the voltage of the power source for the vehicle is directly applied to control valve solenoid 10, and the displacement of variable displacement compressor 2 approaches a maximum.
Control means 14 receives signals from an air conditioning mode-setting device 15 and signals from sensors 16 and transmits a predetermined signal (e.g., duty ratio) to solenoid drive means 11 to exercise optimum control over the compressor's displacement for discharge. The output signal of current detection means 12 and the output signal of voltage detection means 17 for detecting a voltage applied to the solenoid are input to control means 14.